(1) Field of the Invention
The present invention relates to liquid crystal televisions, in particular, to a liquid crystal television in which a substrate mounted with an audio signal processing circuit is arranged on the rear face side of a liquid crystal panel.
(2) Description of Related Art
In general, televisions have audio signal processing circuits that generate audio signals and output the audio signals to speakers attached to cabinets to thereby reproduce audios. Japanese Unexamined Patent Application Publication No. 9-327083 discloses a technique wherein a speaker is connected to a connector arranged on a substrate with a lead wire, through which the audio signal is transmitted to the speaker.
Japanese Unexamined Utility Model Application Publication No. 63-74873 discloses a technique wherein an outlet plug is arranged on a substrate, a connector to be fitted with the outlet plug is arranged on a cabinet, and a speaker is connected to the connector with the lead wire in advance, so that the outlet plug and the connector are connected with each other when the substrate is arranged on the cabinet.
Japanese Unexamined Patent Application Publication No. 2005-284053 discloses a technique wherein plural connector terminal groups electrically connected to a liquid crystal panel and a speaker are formed at a connector portion on a flexible substrate, so that the connectors to be connected with external equipments, drivers, and the like are collected to a group.
Japanese Unexamined Patent Application Publication No. 2005-130097 discloses a technique wherein in order to fix the cable on the wiring path, plural rib strips are arranged on one of the cabinets and fit-in parts to be fitted with the rib strips on the other cabinet, passing the cable between the ribs in a zigzag form, and fitting the fit-in parts to the rib strips.
Liquid crystal televisions however have lesser spaces for arranging lead wires as compared to cathode ray televisions and plasma televisions, leading to necessary consideration to creeping distance from a power supply circuit (in particular, primary side) and interference with the edges of other components and thus causing the difficulty in selecting the wiring path of the lead wire. The wiring of the lead wire in the conventional liquid crystal television will be described below.
FIG. 7 shows a rear view of a compact liquid crystal television 1 in which the interior of its cabinet are shown with a rear cabinet of the compact liquid crystal television 1 removed. Conventional liquid crystal television has a substrate and a speaker connected thereto as shown in FIG. 7.
A liquid crystal panel 2 has a display face facing to a front cabinet 1a. The top and bottom faces, left and right side surfaces, and a rear face of the liquid crystal panel 2 are covered with a metal case, on which rear face various substrates are mounted and fixed. The front cabinet 1a has a space whose lower side is not used for arranging the liquid crystal panel 2. To the left and right of the space a left speaker 6 and a right speaker 7 are attached respectively and to the central part of the space a sensor substrate 5 is attached. The sensor substrate 5 includes a light receiving circuit for receiving a remote control signal, and an LED for notifying the state of the liquid crystal television 1.
On the rear face of the liquid crystal panel 2, a digital substrate 3 and an analog substrate 4 are arranged. On the upper side of the analog substrate 4, formed is a square cut-out portion, in accordance with which the digital substrate 3 of a substantially rectangular shape is arranged. On the digital substrate 3, a digital image signal processing circuit is mounted, where the processed image signal is output to the liquid crystal panel from an LVDS terminal on the upper end. On the analog substrate 4, an inverter circuit 4a is formed in the region from the right side to the upper right, and a power supply circuit 4b is formed in the lower right region. Furthermore, a tuner circuit including a tuner 4d, an audio signal processing circuit including an audio amplifier 4f, an analog signal processing circuit 4e of input/output circuit etc. including a jack 4c are formed in the region from the center to the left side of the analog substrate 4.
Regarding the audio signal output from the audio amplifier 4f, the right channel is output to the speaker 7 via a connector 7a and a lead wire 7b, and the left channel is output to the left speaker 6 via a connector 6a and a lead wire 6b by the pattern formed on the analog substrate 4. Since the lead wire 6b is wired at a position close to the power supply circuit 4b, UL tube is attached for ensuring the creeping distance. The UL tube is a tube made of flame retardant rubber, which suffers from high cost by about 0.2 US dollars per tube.
The power supply circuit 4b is formed along the lower side end of the analog substrate 4 in order to reduce the creeping surface with other circuits and to keep the weight balance of the entire liquid crystal television 1, resulting in that the lead wire passes near the power supply circuit 4b regardless of the position of the analog substrate 4 the lead wire is pulled out. Thus, the UL tube must be used for the lead wire, and high cost is inevitable. Such problem cannot be solved with the techniques of the documents described above.